Field
Aspects of the present invention generally relate to a radiation imaging apparatus equipped with a radiation detection unit configured to detect radiation transmitted through a subject and to convert this radiation into an electric signal, and having an opening at a part of its casing.
Description of the Related Art
With the recent progress in semiconductor processing technology, a digital radiography (DR) apparatus configured to take a radiation image using a semiconductor sensor has come to be widely used in the medical field. As compared with a conventional radiation photography system employing a photosensitive film, this system exhibits a very wide dynamic range, and is advantageous from the practical point of view in that it can obtain a radiation image not affected by fluctuations in radiation exposure amount.
Use of this apparatus is expected in every conceivable case in and out of hospitals. Since satisfactory portability and operability are required of this apparatus, a reduction in size, thickness, and weight of the apparatus is in progress. In addition, taking the general versatility of the apparatus into consideration, the thickness of the apparatus is required to be restrained to approximately 15 mm so that the apparatus can be inserted into a Bucky's unit used in a conventional film cassette. From the viewpoint of improving the portability and operability of the radiation imaging apparatus, the cable for supplying power to the imaging apparatus is very inconvenient. Further, there is a fear that a person may be caught by an extra cable and fall down, or may damage the imaging apparatus and the control unit. Further, in a clean (sterilized) environment such as an operation room, the imaging apparatus inclusive of the cable is prohibited to come into contact with an un-sterilized area such as the floor surface. To solve the above problems, a wireless type DR apparatus has come to be widely used.
In the wireless type DR apparatus, a power supply source for supplying power to the apparatus is indispensable. Some DR apparatuses have a built-in power supply source, which is not detachable. DR apparatuses, however, in which the power supply source is detachable have also come to be widely used. In this detachable type apparatus, an opening is provided at a part of the casing thereof, and a member for storing a battery is mounted to that opening (See Japanese Patent Application Laid-Open No. 2012-63326). According to Japanese Patent Application Laid-Open No. 2002-311527, a cover is provided at the opening, thus taking airtight property into consideration. There exist a lot of wired type apparatuses each having a power cable, each of which is provided with an access cover for the replacement of the cable and the replacement of the electric board.
The above-described radiation imaging apparatuses are often used in direct contact with a patient in every possible condition, so that, after the use, the radiation imaging apparatus is subjected to cleaning, disinfection, sterilization, and the like without fail. At that time, in order to effect the above-mentioned disinfection and sterilization, there is frequently used, instead of water, an organic solvent or a liquid containing a sterilizer.
A DR apparatus contains a lot of electric boards, and if liquid enters the DR apparatus, failure or ignition of these electric boards may occur. In particular, in a case of a DR apparatus having an access cover, a gap may be formed between the access cover and the casing exterior, and, in a case of a DR apparatus having a detachable battery, a gap may be formed between the battery and the battery storage portion, or between the battery storage portion and the casing exterior, which leads to an increase in the risk of intrusion of the above-mentioned liquid. When the opening is exposed at the time of replacement of the battery or for temporary maintenance of the imaging apparatus, there is a fear that liquid will easily enter the interior of the imaging apparatus.
Further, in such a structure, there is also a fear of leakage of light through the above-mentioned gap. As is generally known, the radiation light receiving portion (sensor portion) of a DR apparatus is deteriorated by light. To fill the gap, the parts are glued to each other by adhesive, or the parts are given pressure, for example, by fastening them together by screws with a seal member or the like being held therebetween. In the former case, when a trouble such as damage of either of the parts glued together occurs, an increase in the cost due to the replacement of the part is involved, resulting in an unsatisfactory maintainability. In the latter case, the casing exterior and an inner component of the DR apparatus are fastened together, so that, when the DR apparatus is dropped down, all the weight of the apparatus interior must be supported by the fastening screws. Therefore, the screws and the portion around the fastened portions may be easily damaged. If, fearing this, the fastening by the screws were eliminated, a repulsive force striving to compress the seal member to a desired thickness may be increased, and the portion around the opening may be swollen. The solvent or the like exhibits a much lower surface tension than water, and more easily enters the gap. Thus, if the seal member is not compressed to the desired thickness, there is a fear that the liquid may enter the interior of the imaging apparatus.